Automatic stop for dies



Sept. 16,1952 n.KRAsaERG 2,610,536

' AUTOMATIC STOP FQR DIES I Filed Aug; 23, 1947 INVENToR.

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Patented Sept. 16, 1952 UNITED STATES PATENT vOFFICE,

2,610,686 i AUTOMATIC STOP Fon DIES Rudolf Krasberg, Chicago, ll. Application August 23, 1947, SeralNo. 770,287 3. claims. (o1. 164-59) bling-g and accurately positioning the stop mecha.-

nisnr with. respect to. thework to be operated upon..

In generahthe invention' contemplates the provision. of an automatic stop mechanism for a punch. press. or similar: device of the type which includes/a reciprocatingy tool head carrying ar punchlor. othertool, Whichfreciprocates in registeringopenings ina die block and a stripper plate-.carried thereby. The stripper plate is provided Witl'iaV channel through which the Work, usuallya sheet metal strip of varying dimensions, isv fed.; Such'stop mechanisms usually include` a1 pivoted stop' lever or. rocker arm having at one: end thereof-an. angularly disposed finger or pin which. servesas. the work engaging, stop. Thus,y the; stop nger is adapted to engage the edge of the. work within the previously punched opening; therethrough sov as to properly position and'. gauge the work.r for the succeeding punching operation.' Heretofora'. each diiferent job necessitated theprovision. of a special size of stop lever dependingupon. the type of operation to be performed, the sizeof. the work', and the particular form ofdie and stripper sets. Thus, one die might require a lever having alonger distance from the pivotal mounting therefor to the stop finger atA the end thereof so that an entirely new stop lever wouldhave to be made. Likewise, thefstop leverhadto beconstructed to meet the requirementsnecessitated by any particular type off stripper plate. Thus, the formation of each ne-wfstop` mechanism was in effect atool makers job. requiring-` a numbery of. hours.. ofy specialized Work-v Withthefabove inmind, itis one. of the principal objects.otthefpresentinvention to provide anautomati'c. stop. assembly having. standard size parts which. may be. assembled in any desired positionoff'adiustment, thus adapting it for differentinstallations. andmaking it. possible for. a toolroonLto carry asupply of standard parts. so aste. obviate the.A necessity of. completely forming anew stop mechanism for eachob.

. Another object of the invention isv to provide anautomatic. stop. assembly which. includes. a standard size lever. arm and. a simplified .pivotal: support. therefor, the parts being. relatively adjustable-duringassembly` to' adapt the asse bled stop mechanism for. a variety of. installa.-

tions..

A further object. of the invention. is to. pro.- vide-an automatic stop mechanism. of the above .type Whichis constructed andarranged so asjto be readily applied both above and below the stripper plate andeither. for left or. right. hand feeds. g y y A still further object ofthe invention is. to provide an. automatic stop. mechanism. of.. the above type wherein thev pivotally mountedsupportfor the. lever. arm` is of. simplified sheet-metal constructionandwhich carries means for securing the llever arm in.. the. predeterminedA adjusted yposition thereof.

o `A. still further object.. ofthe invention is to provide an. automatic stop assembly ofthe above type wherein the lever arm and the. pivotalsupport therefor have slight permissive sidewise movement` in addition to the oscillating. pivotal movement to assure proper positioning of the stop finger on the faceof. the Work after each punching or other. operation.

The invention still further aims to provide an assembly ofy the above type which is simple in construction, whichcan be readily assembled. and adjusted, and. which. includes a minimum numfber ofparts.

The above andother. objects ofthe invention will in part. be obvious-and. will. be: hereinafter more fully pointedout.

Inthe accompanying drawing:

Figure l is a top plan. viewy showing the stripper plate and stop mechanism;

K Figure 2.is asectional view taken substantially along `the line 2-2 of Figure. 1 and showing the punch. and tappet mechanism;

Figure 3l is a longitudinal. section.. taken.. substantially along the-line: 3-'3 of Figure-1;y

Figure 4.v is ,an` enlarged. section. taken.. along .the linev 4.-4 of Figure 2" and showing pivotal mountingfor the stop lever;

Figure 5 is an. enlarged fragmentary perspective view showing the stop lever andthemanner in. which it is accuratelymeasured and. located before. nal installation;

Figure 6 is an enlarged perspectiveview of. the stop finger and. showing the. recesstherein. by means'. of which` itv is secured. toy the pivotal. suppor Figure 7 is anfenlarged detail sectionalview takensubstantially along,.- the-linenl`| ofY Figure 2,y and showing. the conn'ectionfbetween the lever` arm and .its pivotal'. support Figure l8 is a detail view similar to Figurev l 3 of a modiiled stop lever in which a single spring is incorporated to act upon the lever; and

Figure 9 is a sectional View similar to Figure 2 showing the modified form of spring construction of Figure 8.

Referring more in detail to the accompanying drawing, the invention is illustrated in connection with a punch press which includes a bed plate HI carrying a die block |I. The die block |I is provided with a vertical aperture I2 into which the punch or other tool reciprocate-s during operation upon the work. A stripper plate I3 is secured by bolts |4 or the like to the upper face of the die block II and is provided with an aperture I5 registering with the die block aperture I2 and through which ythe punch or other tool reciprocates. In addition to this aperture I5, the stripper plate is provided with another and smaller vertical aperture I6 therethrough which is located in advance of the tool with respect to the line of feed of the work. As illustrated in the drawing, there is a laterally extending open channel I1 in the upper face of the stripper plate I3 and this channel communicates with the vertical aperture I 6. As will be hereinafter pointed out, the stop lever or rocker arm oscillates within this channel but such channel construction is not essential as the stop mechanism may be mounted on the stripper plate so that only the finger portion thereof extends through the vertical opening I6, if desired.

A punch I8 is carried by a reciprocating tool head I9 to which is secured a spring arm or tappet by means of bolts 2| or the like. The stripper plate I3 is provided with downwardly open recess 23 which forms with the adjacent face of the die block a guide passage through which the work W is fed. Thus, during feeding of the work through this passage, the tool head I9 reciprocates with the punch I8 reciprocating in -the aligned apertures I2, I5 in the die block and stripper plate, respectively.

The mounting for the stop mechanism is in the form of a sheet metal bracket 24 having laterally extending ears 25, 25a which are secured by bolts 26 or the like to the side edge of the stripper plate |3, although this bracket may be secured at other locations on the stripper plate as desired and depending upon the operation to be performed. The bracket 24 is provided with forwardly or outwardly extending side portions 21, 21a having the bottom edges thereof joined by a portion 28 so as to provide a U-shaped yoke portion.

The stop lever arm 29 is more particularly illustrated in Figures 5 and 6 and is formed from rectangular bar stock having a body or shank portion 3U and an angularly disposed end portion 3| which forms, in the illustrated embodiment of the invention, a depending stop finger for engaging and positioning the work in a manner to be hereinafter more fully pointed out. As shown in Figure 6, the shank or body portion 3U has a recess 32 formed transversely in the upper surface thereof and the location of this recess will depend on the particular details of the operation to be performed.

The pivotal support for the lever arm is formed of sheet metal and is substantially in the form of a bracket 33 having a top portion 34 with depending side portions or Wings 35, 35a intermediate the ends thereof. The wings are apertured, as at 36, to receive a pivot pin 31 therethrough. At the ends of the -top portion 34 of the bracket or pivotal support 33, the material thereof is continued downwardly and inwardly as at 38, 38a to provide aligned end openings each having a squared cross section corresponding to the cross section of the shank 30 of the stop lever so ythat it will snugly t therein. The top portion 34 of the pivotal supporting bracket is cut away to provide two or more spaced openings 39, (tea which are separated by a strap member 40. The strap 4|] is adapted to be depressed into the recess 32 in the shank of the lever arm so as to secure the same against endwise movement relative to the pivotal support therefor.

With the lever arm and pivotal support therefor assembled together. the depending side portions 35, 35a of the supporting bracket are tted within the U-shaped yoke portion between the side portions 2T, 21a of the supporting bracket 24 and the pivot pin 31 is suitably mounted in apertures in these side portions 21, 21a. A coil spring 42 encircles the pivot pin 31 with one end 42a thereof bearing against the shank or body portion of the lever arm remote from the stop finger 3| and with the opposite end 42h thereof bearing against the bottom portion 28 of the U-shaped yoke portion. The coil spring 42 thus operates, as particularly illustrated in Figure 2, to normally urge the entire stop assembly in a clockwise direction tending to force the stop iinger 3| toward or into engagement with the Work W being operated upon by the machine.

As shown in Figure 4, there is slight clearance between the apertures 36 in the depending side portions 35, 35a of the pivotal supporting bracket 33 and the pivot pin 31 and similarly there is slightvclearance between the side portions 35, 35a of the pivotal supporting bracket and the side walls 21, 21a of the stationary supporting bracket 24. Thus, the assembled pivotal supporting bracket and the lever arm may shift slightly laterally within the yoke portion of the bracket 24. A spring 43 has an angular extension 43a which is secured between the head of the bolt 26 and the laterally extending ear 25 on the bracket 24. The free end 43h of the spring 43 bears against a depending side portion of the pivotal supporting bracket 33 so as to normally resist this lateral shifting or wobbling of the assembled Apivotal supporting bracket 33 and the lever arm 29. Thus, the spring 43 as viewed in Figure l, normally urges the lever arm and stop ilnger 3| in a direction opposite to the direction of feed of the work through the press.

In assembling the pivotal supporting bracket 33 and the lever arm 29 to complete the rocker arm assembly, a standard size of lever arm has its shank portion 30 fitted into the supporting bracket, as shown in Figure 5, and positioned therein with the stop finger 3| in the exact position of adjustment with respect to the Work which is to be operated upon and as required in the particular installation. After thus positioning the shank 30 of the lever arm, the top surface thereof immediately adjacent opposite sides of the cross strap 40 on the pivotal supporting bracket 33 is scored by a suitable type of metal scriber S. The lever arm may then be removed from the supporting bracket and the recess 32 is formed therein exactly within the scribed lines by a milling or other suitable operation. Then the lever arm is again fitted into the pivotal supporting bracket therefor with the recess 32 disposed immediately below the strap 40. The strap 40 is lthen depressed in a suitable manner so that it snugly engages the shank portion of the lever arm within the recess 32, as particularly shown in. Figure 7'... Thus, relative, sliding movement between. the. pivotal. supporting. bracket. 3.3: and the: leverf arnr Z9; prevented. and the. parts are permanentlyr4 secured.- in-.proper adjusted. position forwthe: workA tof-be" performed. The portion of the lever arm extending outwardly beyond the pivotal supporti may bezcut oiT'and discarded, if desired. It.. will bereadilv seen that-with this manner of yassembling andexactly positioning the stop lever within its pivotal supporting bracket, a supply ofimore'or less standard size stop levers and; brackets may be maintained on hand. for selection and. rapid assemblyy inthe required-.position of adjustment for any particular installation without'` the .necessity of havingacompletelyinew stop mechanism. made up foreach job.

In. operation, the. stock; orwork W is fed throughthechannel 23. formedbetweenthestripperrplate. |:3ianithe die block. til. The ftoolhead {.Bfdescends; andcarries with it the ,punchor other tool;V lil. which passes through the opening; I5 in the; stripperplate. and into engagementl withthe work.. Eurther downward. movement of. the punch cuts through the Work and enters the die opening l2 so as to thus form the initial punched opening O through the work. Upon the return or ascending stroke of the tool, the work is further advanced and the leading edge of the punched opening comes beneath the stop finger 3| on the lever arm, at which time the coil spring 42 will immediately force the nger downwardly into the punched opening. yAs the Work is further advanced, the trailing edge of the initially punched opening will come into engagement with the adjacent edge of the stop finger 3i. reason of the slight permissive lateral movement of the lever arm relative to the bracket 24, the feeding of the work will force the lever arm in the direction of the feeding movement against the action of the spring 43.. The stop nger will ultimately come into engagement withA the adjacent side of the vertical opening I6 through the stripper plate so as to positively hold and position the work against further movement. In this position of the work, the tool head again descends and the punch i8 will punch out the next opening in the work and during this downward movement of the tool head, the tappet 20 will engage the top surface of the pivotal supporting bracket 33 and tilt the entire lever arm assembly in a counterclockwise direction, as viewed in Figure 2, so as to elevate the stop finger 3| above thetop surface of the work, the opening 16 being of `sufficient size to permit this movement. When the stop finger becomes disengaged from the edge of the previously punched opening, the spring 43 operates to immediately shift the lever arm laterally in a direction toward the tool and opposite to the direction of feed of the work so as to positively shift the stop finger out of alignment with the opening and to assure that when the tool head has ascended and the spring 42 again comes into operation for shifting the lever arm in a clockwise direction, the stop finger will be over an unpunched portion of the work and will not descend into the opening from which it was previously removed. This periodic oscillation of the lever arm and its stop finger continues throughout the punching operations.

In Figures 8 and 9 a modified form of spring construction is shown. Instead of using a multiple spring construction for shifting the lever arm as shown in the other views, a single spring 44 is employed. It will be noted that this spring acts on two sides of the lever arm simultaneously einem inthe sametmannerthatthemultiplesprnconstmctionprcviouslx. describedacisuponthelever arm.. spring.. construction makes for simplicityfaneconomyindesgn.

foregoing descri tion, preciated; that/use. of.' the. stop, mechanism of. the presentinvention. will.. effect, a substantial saving oftime. and expense. in variousY punching, stamping. or similar operationsbyl eliminatingY the necessity; of completelgmakingi up. a new stop levery for; eachy diierenttype. of operation to be performed.. Thus,.byproviding a. supply of standard sizelever. arms-and pivotalsupporting brackets therefor., the;l partsv may be.l relativelyy assembled in, various positions requiredv over. a wide rangeofshapesand-sizesof. blanks Ato beoperated upon and various. types ofV stripper platesv and other diet mechanisms.. Therefore, the` stop assembly of thegpresentinvention is` in the nature of. a universal.. stop-in. that the standard. parts may` be. assembled. to operate. over a wide. range of specifically different.y installations. True,4 the crossv section ofthe. lever arm may have tov be taken into consideration in connection with the operation to be performed and also the size of opening in the stripper plate. However, with a very few different cross sectional sizes, a tool room may be equipped with a supply of lever arms of various cross sections and pivotal supporting brackets therefor and thus obviate the necessity of taking the several hours which normally are required of a tool maker to make up a new stop lever for each different installation or operation. By using the standard parts of the present invention, a new stop mechanism can be formed in a matter of a very few minutes by the location and marking of the lever arm in its supporting bracket as pointed out above. It is obvious that the lever arm may be formed of bar stock of other than square cross section and if from round stock, the engagement of the strap in the recess formed therein would properly lock the parts together.

While one form of the invention has been shown for purposes of illustration, it is to be clearly understood that various changes in the details of construction and arrangement of parts may be made without departing from the scope and spirit of the invention as set forth in the appended claims.

I claim:l

1. A punch press or the like comprising a die and stripperplate assembly, a reciprocating tool mechanism, a rocker assembly including a sheet metal supportingy bracket, means for pivotally supporting said bracket from said die and stripyper plate assembly, and an arm secured and carried solely by said supporting bracket and having a transverse recess formedin the surface thereof at a pre-selected position with respect` to said bracket, a portion of said bracket extendingr into said recess for maintaining said arm in the preselected position of adjustment, said arm having f a stop portion adapted to successively engage and position the work during passage thereof through the die and stripper plate assembly, means carried by the tool mechanism for shifting said rocker assembly in a direction to move said stop portion out of engagement with the work, and

spring means for returning said rocker arm with n lsaid stop portion in work engaging position.

2. A rocker arm assembly adapted for use as an automatic stop with a wide range of different die sets in punching and similar machines and f comprising a supporting bracket having sleeve portionsat the ends thereof and depending interit, will.. be ap? mediate side walls adapted to be pivotally connected to the die set, said bracket having a plurality of cut-outs across the top thereof forming at least one strap between said cut-outs and extending substantially transversely of said bracket, and a stop lever snugly tting within the sleeve portions on said bracket and adapted to be shifted therein to a pre-selected position of adjustment depending upon the requirements of the die set and operation to be performed, andY having a recess formed immediately beneath said strap whereby upon depression of said strap into said recess the stop lever and supporting bracket are maintained against relative movement.

3. The method of accurately positioning a substantially standard size stop lever with respect to the work to be operated upon in a punch press or like machine, which method comprises in locating the stop lever in a support in exact adjusted position for the Work to be fed through the machine, marking an area of the stop lever through openings in the support, removing the material of the stop lever between the markings 8 to provide a. recess, shifting the stop lever to the previous position of adjustment and depressing a portion of the support into said recess for securing the parts against relative movement.

RUDOLF KRASBERG.

REFEREN CES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS 

